In a wireless cellular communications system, there are two directions of data transmission: downlink and uplink. The downlink refers to data transmission from a base station to a user terminal; and the uplink refers to data transmission from a user terminal to a base station.
In addition, in a scenario of a cell handover in the wireless cellular communications system, a user terminal may perform data transmission with multiple base stations, that is, the user terminal may be associated with at least two base stations, and transmits data to them.
In the prior art, the user terminal only can transmit data to one base station within one time segment and transmit data to another base station within another time segment, that is, cannot transmit data to two base stations within one time segment simultaneously, thereby causing that transmission efficiency of data transmission of the user terminal is relatively low.